GNU bug report logs - #33034
`unwind-protect' cleanup form is not executed if body dies in stack overflow

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Message #37 received at 33034-done <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Paul Pogonyshev <pogonyshev <at> gmail.com>
Cc: 33034-done <at> debbugs.gnu.org, Eli Zaretskii <eliz <at> gnu.org>
Subject: Re: `unwind-protect' cleanup form is not executed if body dies in
 stack overflow
Date: Sun, 14 Oct 2018 10:02:59 -0700

[Message part 1 (text/plain, inline)]

Thanks for the bug report; I installed the attached to fix it. The problem with 
your test case was neither C stack overflow nor failure to unwind the Lisp 
stack: it was failure to restore the Lisp evaluation depth (which is a separate 
thing from the Lisp stack size).

By the way, why are there two different limits? That slows the interpreter down 
a bit.  Why don't we simply have a limit for the Lisp stack size? Every time 
lisp_eval_depth grows, the stack size grows, so limiting the stack limits the 
evaluation depth for free. If we had done things this way, the interpreter would 
be a bit faster and this bug would never have occurred.

[0001-Fix-lisp_eval_depth-in-unwind-protect-cleanup.patch (text/x-patch, attachment)]

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